In the November issue of Arthritis & Rheumatism, a study reported that rheumatoid arthritis related joint damage appears to be more severe for those with a normal body mass index (BMI) than for those who are obese. However, only obese patients with a positive rheumatoid factor appeared to have less joint damage. The finding that having a normal weight was a risk factor for people with RA runs directly counter to most research, which shows that normal weight is more beneficial for one's health.
Scientists at the German Rheumatism Research Centre in Berlin evaluated 767 patients with early RA over a period of three years. Forty percent of the patients had a normal BMI, 41 percent were overweight and 19 percent were obese. The average score on a standard rating scale for joint damage seen on x-rays among the patients with a normal BMI was 9.7 in those who tested positive for rheumatoid factor and 4.6 among those who tested negative. There was no statistical difference in corresponding scores among obese patients -- 4.1 versus 3.4, respectively.
Before people with RA trying to diet or maintain a healthy weight, it's is important to note some observations of the researchers that have not really mentioned in news articles related to this study. First, people with a normal BMI tended to have greater joint damage at the beginning of the study. Second, the researchers observed that one key trait in the results may be the patients with positive RA factor versus negative RA factor. The scientists pointed out that more large studies need to be conducted to determine the effect of both BMI and positive or negative rheumatoid factor on people with RA. Also, the scientists found no association between weight loss or gain and disease activity or joint damage. Weight loss was not associated with higher disease activity or more joint damage. The scientists didn't explain why they thought people of normal weight began with more joint damage than obese people, except to compare it to results of studies that show that people with low BMI are more likely to develop osteoporosis than people who are overweight. I wonder if people of normal weight at the beginning of the study had more joint damage in part because they were more active and therefore more wear and tear on the joints from activity caused the high baseline numbers.
The scientists emphasized that even though the results may make it seem like obesity for RA patients may be a good thing because it may lessen joint damage; it still increases pain, functional disability and impairs health and quality of life for people with RA. In other studies reported recently, being overweight was found NOT to increase the risk of dying from heart disease, cancer, accidents and diseases like Alzheimer's. The study looked only at death rates, not overall health. Being obese however, has been associated with higher risk of death from heart disease, diabetes, kidney disease and several cancers such as breast, colon and pancreatic cancer. Personally, I would rather be a healthy weight and run a greater risk of joint damage and osteoporosis than be obese with less joint damage but at a greater risk for cancer, heart disease and diabetes.
Published On: December 13, 2007